A bevel head replaceable rotary tool has heretofore been known having a shaft-like tool body and a bevel head formed as a separate body from the tool body with the bevel head arranged to be detachably mounted on the tool body at a leading end thereof in concentric relation thereto for use. A drill, disclosed in Patent Publication 1, represents such an example in which a bevel head is integrally fixed to a tool body by means of two fastening screws with both components having mating surfaces formed with radially extending concave and convex portions through which torque is transferred. With such a bevel head replaceable rotary tool, the tool body can be reused upon replacement of only the bevel head when tool life is reached due to wear of a cutting edge or the like. This is more economical when compared to a case in which a whole of the tool is replaced with a capability of achieving effective utilization of resources.
Patent Publication 1: Japanese Patent Application Publication No. 2003-136319